Process for obtaining flocked fabrics and fabrics obtained therefrom

ABSTRACT

A process for producing a fabric laminate by coating a suitable substrate with a curable adhesive flocked binder, flocking the coated substrate with a flocked material composed of multifilament fibers, the individual filaments of which are temporarily adhered to one another by a removable binder, permanently securing the flock in the coating by subjecting the laminate to a curing operation, and then removing the temporary binder from the secured flock. The flock substrates obtained from this process exhibit unusual surface effects similar to those of a tufted fabric. Also, the present process can be used for flocking relatively long, fine denier filaments.

United States Patent Halloran Nov. 25, 1975 [54] PROCESS FOR OBTAINING FLOCKED 3,277,564 10/1966 Webber et al. 29/419 FABRICS AND FABRICS OBTAINED 3,697,238 10/1972 Brown et al. 117/17 X THEREFROM John B. Halloran, Somerset, Mass.

Assignee: United Merchants and Manufacturers Inc., New York, N.Y.

Filed: Aug. 1, 1973 Appl. No.: 384,599

Inventor:

References Cited UNITED STATES PATENTS 4/1952 Saks 117/33 X 10/1954 Saks..... ll7/l7 X 8/1959 Klein 117/33 X Primary ExaminerMichael Sofocleous Assistant ExaminerShrive P. Beck Attorney, Agent, or FirmMichael A. Caputo; John P. McGann ABSTRACT A process for producing a fabric laminate by coating a suitable substrate with a curable adhesive flocked binder, flocking the coated substrate with a flocked material composed of multifllament fibers, the individual filaments of which are temporarily adhered to one another by a removable binder, permanently securing the flock in the coating by subjecting the laminate to a curing operation, and then removing the temporary binder from the secured flock. The flock substrates obtained from this process exhibit unusual surface effects similar to those of a tufted fabric. Also, the present process can be used for flocking relatively long, fine denier filaments.

7 Claims, 3 Drawing Figures A A .IIlIIIIIIIlIlllllIll|llIlll'llllllllllllllllllll PROCESS FOR OBTAINING FLOCKED FABRICS AND FABRICS OBTAINED THEREFROM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to the field of flocked fabrics and laminates. More particularly, this invention concerns a method for producing fabrics having unusual textured and tufted effects by use of a flocking treatment.

2. Description of the Prior Art Textile fabrics comprising laminates of raised fibers, such as, a flock or pile, secured to a base or substrate material by an adhesive binder are well known. Additionally, various methods for texturizing or producing patterned effects-in such textiles are known. Generally, these include chemical methods, such as, chemical shrinking techniques, and physical methods, such as mechanically cutting, compressing, or compacting areas of the upstanding fibers of the flock or pile.

These methods, however, tend to require complicated equipment resulting in relatively high production costs. Additionally, it is difficult to produce patterns which are permanent to washing or dry cleaning.

A very popular type of fabric having relatively short fibers is that produced by fine gauge tufting (five sixtyfourths gauge and finer). Such fabric is conventionally used in the upholstery, outerwear, and sportswear areas. The production of this type of fabric which is essentially a low pile tufted material having a velvet type effect, requires relatively complicated and expensive machinery. Consequently, such fabric is relatively expensive.

The production of flocked fabric using relatively long fibers in order to simulate furs and the like has not met with much success in the commercial areas because of the inherent difficulties of subjecting such long fibers to a flocking process. Consequently, the production of fabrics of this type has usually required a relatively complicated process, e.g., sliver knitting, and the like.

SUMMARY OF THE INVENTION I have discovered a method utilizing known flocking techniques which can produce a fabric or flocked substrate suitable for use in place of fine gauge tufted fabrics. Additionally, by virtue of the present process, it is possible to simulate sliver knit type fabrics by using a comparatively simple flocking technique.

Particularly, the present invention comprises coating a suitable substrate with a curable adhesive flock binder, flocking the substrate with a flock composed of multifilament fibers, the individual filaments of which are temporarily adhered to one another by a removable binder, permanently securing the flock in the flock binder, and removing the temporary binder from the thus secured flock.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a pictorial cross-sectional representation of a flocked substrate at the next to final stage of the present method.

FIG. 2 is a cross-sectional pictorial representation of a flocked substrate after the final step of the present invention.

FIG. 3 is a schematic diagram of the process of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 3, the process of the present invention may be carried out as follows: a roll 12 of substrate material 14 suitable for flocking is unwound'in the direction indicated by arrow A. The substrate 14 may be any type of material suitable for a flocking operation, such as, woven or non-woven fabric, foamed or unfoamed plastics, paper, and the like. Typically, suitable flexible substrates include polyvinyl and urethane films, fabrics composed of cellulose-based fibers, e.g., rayon or cotton, and synthetic and natural fibers. Particularly preferred blends are those of cellulose-based fibers, wool, mohair, silk, acrylics, modacrylics, and the like.

Suitable rigid backings include such materials as masonite, wood, glass, metals, fiberglass laminates, and the like. Understandably, such rigid substrates cannot be dispensed from a roll such as that depicted in FIG. 3, but would normally be fed into the process as flat sheets.

Substrate 14 is conveyed by conveyor 30 under a coating knife 16 whereby a thin coating of a flocking adhesive or binder is applied.

Any type of flock binder or adhesive may be used in the present process. Such adhesives are well known in the art and are generally classified as water base and solvent base adhesives.

Water base adhesives consist of a binder, generally an emulsion polymer and a viscosity builder. They may also contain plasticizers, thermosetting resins, curing catalysts, stabilizers and other additives well known in the art.

The emulsion polymers generally used include acrylic, vinyl-acrylic, vinyl, urethane and styrenebutadiene latexes.

In order that the upstanding fibers be held in the desired position until the adhesive is fully cured, it is generally necessary to raise the viscosity of the latex to about 2 to 100 thousand centipoises. The viscosity is dictated by the nature of the backing and the method of contacting the upstanding fibers with the adhesive layer. For example, where the backing is a loose weave fabric and the beater bar method is employed, a viscosity of from to thousand centipoises or higher will be necessary to prevent undue penetration of adhesive into the backing which would result in a boardy hand and would leave insufficient adhesive on the surface to securely bind the fibers. On the other hand, where a relatively impervious backing is used, a much lower viscosity, e.g., about 20 to 30 thousand centipoises is sufficient.

Suitable thickeners include water soluble polymers, such as, carboxymethyl cellulose, hydroxyethyl cellulose, poly-oxyethylenes, and natural gums, as well as, alkali swellable polymers, such as, highly carboxylated acrylic emulsion polymers, and the like.

Plasticizers may be added to alter the hand of the finished goods or to improve the flow and leveling characteristics of the adhesives. Where the primary goal is the latter, fugitive plasticizers, such as, the phthalate esters may be employed. If the intent is to alter the hand of the finished goods, then more permanent plasticizers, such as, low molecular weight polyesters may be used.

Thermosetting resins, such as, methylol-melamines, urea formaldehyde condensates or phenol-formaldehyde condensates may be incorporated to improve durability or abrasion resistance of the finished goods.

Catalysts, such as, oxalic acid or diammonium phosphate can be used to increase the rate of cure of the adhesive.

More specialized additives include ultra violet absorbers where the backing, such as a urethane foam, is subject to photo degradation, and dyes or pigments to impart a color to the adhesive layer. When a breathable film is desired, adhesives may be chemically or mechanically foamed.

Solvent adhesives include both fully reacted soluble polymers, such as, acrylic homo and copolymers, polyesters, polyamides, or polyurethanes and two package systems, such as, polyester polyols with diisocyanates or isocyanate prepolymers and epoxies with polyamines. The polymer or prepolymer is dissolved in a suitable solvent which is preferably low boiling, and then thickened to the proper viscosity in a manner similar to that used for the water base adhesives. Catalysts, crossliking agents, stabilizers, pigments, or dyes may also be incorporated.

The substrate is conveyed at a speed generally within the range normally used in commercial flocking processes, e.g., 25 to 150 ft./min.

Thereafter, the coated substrate passes through flocking box 18. The flocking box may be any type conventionally used in the art, such as, the beater-bar type or an electrostatic flocking unit.

Suitable materials for use as the flock fibers include rayon, cotton, nylon, polyesters, wool, mohair, silk, acrylics, modacrylics, and the like. Such flock is normally short fibers or filamentry material, generally less than one-fourth of an inch in length. However, in accordance with the present invention, the flock fibers may have lengths of three-fourths of a millimeter up to 8 millimeters and even longer.

Additionally, the fibers which are used as flock in the present process are composed of multifilament yarns. That is to say, each of the pieces of flock is made up of a multiplicity or bundle of filaments which are adhered together by a temporary removable binder. Such flock material may be made in much the same manner as a normal flock fiber with the exception, of course, that multifilament rather than monofilament fibers are used. Additionally, the multifilament fiber must be treated with an appropriate temporary adhesive material or size prior to cutting into flock.

Of course, the present process may be carried out with multifilament yarns or fibers having any number of filaments and of any denier size.

Any type of adhesive material which will serve the purpose of temporarily securing the filaments of each given fiber to one another for a period of time sufficient to carry it through the process as hereinafter described is suitable for use in the present process. Typically, sizes which are well known in the art such as starches, chemically treated or modified corn or potato starches, polyvinyl alcohol, sodium carboxymethyl cellulose, polyacrylic acid, natural gums, amylose functional derivatives, hydroxyethyl cellulose, and the like may be used. Typical sizes are described in Product/72 a publication of Textile Chemist and Colorist, 1972. Understandably, the particular size or adhesive material used is not critical so long as it is readily and simply removed from the fabric. Typically, for example, water or water and enzyme soluble temporary binders are preferred because of the relative simplicity and low cost of removal.

Methods for the application of such sizes, e.g., slashers, are well known to the art (see for example Man- Made Textile Encyclopedia, Textile Book Publishers, Inc., J..I. Press, Ed, 1959, pages 266 277).

It should be noted in this regard, that it is not necessary to remove any of the temporary binder from the ends of the individual pieces of flock in order to make them susceptible to adherence and securement in the binder. Understandably, if this had to be done, the process would be commercially unfeasible.

After exiting flocking box 18, the flocked substrate is conveyed by conveyor 32 to a curing box 24. Curing box 24 is of the conventional type known in the art wherein the binder or flock adhesive is set or cured to permanently secure the flock to the substrate. This is usually accomplished by heating or subjecting the binder to UV irradiation for a given period of time sufficient to fix the binder.

Thereafter, the substrate with the flock thereon is conveyed by conveyor 34 into washing vat 36. Within washing vat 36 is a liquid, usually water, which is effective to remove the temporary adhesive from the flock adhered to the substrate. Understandably, the particular liquid used in washing vat 36 should be one in which the temporary adhesive material is soluble. Thus, this would include water, organic solvents, etc., depending upon the nature of the temporary adhesive binder.

Altemately, washing vat 36 can be replaced by a dyeing step. Such dyeing not only would serve to dye the flocked fabric, but would also function to remove the temporary adhesive. Here again, the type of dye bath used would depend upon the nature of the temporary adhesive, and particular type of dyeing desired, which, in turn, depends on the type of material from which the flock and substrate are made.

After exiting vat 36, the substrate is subjected to a drying step 40, which may be any type of conventional drying treatment sufficient to remove the residual liquid from vat 36 from the fabric. Thus, for example, air drying and the like, all of which are well known in the art and at the disposal of the skilled art worker may be used. Thereafter, the dried finished fabric is wound on to roll 42.

Referring now to FIGS. 1 and 2, FIG. 1 illustrates a pictorial representation of a cross-section of the flocked substrate after it has exited curing box 2 and is essentially at point X on the schematic diagram of FIG. 3. Thus, as shown in FIG. 1, the individual filaments of upstanding fibers D are essentially stiff and are disposed side-by-side to each other, i.e., they are stuck to one another to form a single bundle.

FIG. 2 represents the flocked laminate of the present invention after it has exited drying box 40. Thus, the temporary adhesive material has been removed from the filaments and the individual filaments of each fiber have spread out in a blossoming or mushroom fashion. Note however that the end of the fibers which are secured in the flocked binder still retain their configuration relative to one another. As a result of this blossoming, the final product obtained exhibits rather dense coverage by the flocked fibers and produces a tufted visual effect.

As noted hereinabove, by use of the present process wherein the fibers to be adhered to the substrate by flocking are secured together by a temporary binder, extremely long fibers of low denier may be utilized for flocking, e.g., 8mm fibers of 1.5 denier. Heretofore, it has been extremely difficult to handle such fibers by a flocking type process simply because of the physical problems inherent with such long fibers. Consequently, when flocking long fibers in the past, a certain denier to length ratio was required. Typically, for example, to successfully flock 8mm fibers, the denier had to be about 60. Understandably, the fabrics obtained with this type fiber possessed an undesirable bristly feel.

The following example further illustrates the present invention.

300 denier 240 filament bright rayon yarn which was sized with a 6 percent polyvinyl acetate solution in a conventional slasher was cut into groups of flock having lengths of 0.75, 1.0, 2.0, 3.0, 4.0, and 8.0 millimeters. A polyester/rayon blend substrate fabric (woven) was coated with an acrylic based flock binder and separate samples of the coated substrate were flocked with each of the above identified sized, flocks.

Thereafter, the flocked substrates were dryed and cured and were then dyed using an aqueous direct dye in an open beck. The drying, curing, and dying procedure used were the conventional type steps normally used in the flocking art. The final dryed fabrics exhibited a tufted effect similar to a fine gauge tufted fabric.

Variations, can, of course, be made without departing from the spirit and scope of the invention.

Having thus described my invention, what I desire to secure and claim by Letters Patent is:

1. A method for producing a flocked laminate which comprises:

a. coating a substrate with a curable adhesive flock binder;

b. flocking the coated substrate with particles of flock, each particle being composed of a plurality of filaments disposed side-by-side to each other and being temporarily adhered together by a removable binder to form a single bundle of said filaments, the flocking being carried out in a manner such that one end of each bundle is embedded in the curable binder coating and the bundles are substantially upstanding;

. curing the thus flocked substrate to permanently secure the embedded end of the bundle to the substrate; and

d. removing the temporary binder from the secured bundle whereby the unsecured ends of the filaments of said bundles spread out in a blossom formation.

2. The method of claim 1 wherein the flock is composed of multifilament fibers containing from about 10 to 600 filaments.

3. The method of claim l wherein the flock has a length in the range from about 0.75 to 20 millimeters.

4. The laminate obtained by the method of claim 1.

5. The method of claim 1 wherein the flock is rayon, cotton, nylon, polyester, wool, mohair, silk, acrylic, modacrylic, or combinations thereof.

6. The method of claim 1 wherein the substrate is a polyvinyl film, urethane film, woven or non-woven fabric, fiberboard, wood, glass, metal, or a fiberglass laminate.

7. The method of claim 1 wherein the temporary binder is removed with a solution of dye. 

1. A METHOD FOR PRODUCING A FLOCKED LAMINATE WHICH COMPRISES: A. COATING A SUBSTRATE WITH A CURABLE ADHESIVE FLOCK BINDER; B. FLOCKING THE COATED SUBSTRATE WITH PARTICLES OF FLOCK, EACH PARTICLE BEING COMPOSED OF A PLURALITY OFF FILAMENTS DISPOSED SIDE-BY-SIDE TO EACH OTHER AND BEING TEMPORARILY ADHERED TOGETHER BY A REMOVABLE BINDER TO FORM A SINGLE BUNDLE OF SAID FILAMENTS, THE FLOCKING BEING CARRIED OUT IN A MANNER SUCH THAT ONE END OF EACH BUNDLE IS EMBEDDED IN THE CURABLE BINDER COATING AND THE BUNDLES ARE SUBSTANTIALLY UPSTANDING. C. CURING THE THUS FLOCKED SUBSTRATE TO PERMANENTLY SECURE THE EMBEDDED END OF THE BUNDLE TO THE SUBSTRATE; AND D. REMOVING THE TEMPORARY BINDER FROM TEH SECURED BUNDLE WHEREBY THE UNSECURED ENDS OF THE FILAMENTS OF SAID BUNDLESS SPREAD OUT IN A BLOSSOM FORMATION.
 2. The method of claim 1 wherein the flock is composed of multifilament fibers containing from about 10 to 600 filaments.
 3. The method of claim 1 wherein the flock has a length in the range from about 0.75 to 20 millimeters.
 4. The laminate obtained by the method of claim
 1. 5. The method of claim 1 wherein the flock is rayon, cotton, nylon, polyester, wool, mohair, silk, acrylic, modacrylic, or combinations thereof.
 6. The method of claim 1 wherein the substrate is a polyvinyl film, urethane film, woven or non-woven fabric, fiberboard, wood, glass, metal, or a fiberglass laminate.
 7. The method of claim 1 wherein the temporary binder is removed with a solution of dye. 